Partial neck sizing - a problem?

[VLD Pilot]

I'm bumping back the shoulder on my 224 Valkyrie once-fired bass by .004" in a Redding FB bushing die, and bringing down the neck with a bushing to a neck tension of .003". However, keeping the shoulder bump to .004", I'm seeing the neck get sized only about halfway. I assume this is not ideal and a consistent sizing along the length of the full neck is preferable. Is this true? If so, how do I bring the full length of the neck down to a consistent diameter without pushing the shoulder back far too much?

thxView attachment 198464

That's just how Redding FL bushing dies work. The bushing in the die doesn't size the entire neck only about 2/3. I didn't like it either but it doesn't seem to hurt anything. The die does make contact with the shoulder because it does bump the shoulder back. The bushing just sits too high above the shoulder of the die to get the entire neck before it makes contact with the shoulder. Maybe some other dies do the entire neck but my Redding doesn't either.

 

[Jeffpatton00]

I've used bushing sizing for necks longer than I can remember..
Your standard Redding/Wilson type bushing dies partially size necks, and the length of that much is adjustable.
As far as shoulder bumping/body sizing, this is additional with most 'FL bushing' dies,, and separate adjustable.
There are only a couple die makers offering dies with bushings that include FL neck and shoulder in them.
Some of us bushing or collet neck size with one die, and body size/shoulder bump with a body die in separate operations.
None of this is actual FL sizing, and that's fine.

For consistent neck tension, you should size no more neck length than seated bullet bearing communicates with. From here, you can reduce neck sizing length incrementally during load development, if desired. This length greater/smaller is the true tension adjustment (not seating interference amount).

All new/unturned necks have thicker brass nearest neck-shoulder junction. This is referred to as donut area, which changes over reload cycles. It's detrimental to seat bullet bearing into it, and just as bad to bring it into tension otherwise. Sizing of it does just that, regardless of seating depth.

Even with turned necks, bringing near shoulder neck area into tension is bad. If bullets seat through neck-shoulder junction, you've brought the shoulder angle into tension. If bullets are seated short, as normal, sizing length beyond this will only leave un-upsized neck area binding the bullet-base junction. Either way, this portion of necks will not expand the same as the rest.
It is not as consistent as the simple spring back gripping of bullet bearing, where partial length sizing.

There is actually nothing 'good' with FL sizing of necks, especially when it goes beyond seated bearing length.
While it greatly increases neck tension (to an extreme), just as well it increases tension variance (to an extreme).
There are only a couple underbores, small BR cartridges, that benefit with this anyway. For the rest of us, it's bad in every way. You should never do it.

Hey, Mike, I appreciate your analytical and detailed reply. Thanks.
Jeff

 

[ronstone09]

All I use are Type S dies and they only size about half of the neck. I have never had any problems. Right or wrong I don't bother knowing how much shoulder bump I have. I only shoot for my own pleasure, no competition. I use the Alex Wheeler method for determining how much to size a fired case. I gotta be doing something right!

With those groups I wouldn't do anything different !

 

[30BR]

That's just how Redding FL bushing dies work. The bushing in the die doesn't size the entire neck only about 2/3. I didn't like it either but it doesn't seem to hurt anything. The die does make contact with the shoulder because it does bump the shoulder back. The bushing just sits too high above the shoulder of the die to get the entire neck before it makes contact with the shoulder. Maybe some other dies do the entire neck but my Redding doesn't either.

You can order a F/L sizer (no bushing) from Forster, and tell them what neck diameter you want the neck honed to. (Very minimal charge) This will size down to the shoulder. In some situations that is very helpful.
lately, I am getting good results by squeezing the neck down then opening them up with custom tapered expanders to what a I want. Not at all necessary for a hunting/casual rig. But I am pretty anal...

 

[VLD Pilot]

You can order a F/L sizer (no bushing) from Forster, and tell them what neck diameter you want the neck honed to. (Very minimal charge) This will size down to the shoulder. In some situations that is very helpful.
lately, I am getting good results by squeezing the neck down then opening them up with custom tapered expanders to what a I want. Not at all necessary for a hunting/casual rig. But I am pretty anal...

Thanks for that information

 

[badbull]

While some say .004 is excessive bump I'm not so sure anymore, seems theres more and more BR guys bump that and more.
I'm more in the camp .002-.003.
As long as theres no case head separation problems and your accuracy is were you want it bump .004 I dont think you'll hurt a thing.

I agree, a lot is dependent on the weapon...with my AR rifles .003 bump was not reliable functioning so I went to .004 and had no more problems. I'm using FL sizing dies.

 

[Jeffpatton00]

I agree, a lot is dependent on the weapon...with my AR rifles .003 bump was not reliable functioning so I went to .004 and had no more problems. I'm using FL sizing dies.

And for info, as the OP, my 224V is a semi-auto which is why I was thinking of a slightly greater bump on the shoulder than I would use for a bolt action.

 

[30BR]

I agree, a lot is dependent on the weapon...with my AR rifles .003 bump was not reliable functioning so I went to .004 and had no more problems. I'm using FL sizing dies.

If you are bumping more than about .001 when the handle will fall freely (with firing pin out), you are actually fire forming everytime you shoot.
Having said that, semi-autos need some clearance because the spring is all that will close the bolt; not a bicep.

Check out this video series:

 

[Jeffpatton00]

Circling back on this - I did bump my shoulder back .004, but found that the bodies hadn't been sized enough all the way to the base, and the case diameter ended up too large in the last half or 3/4" to allow the bolt to go into battery. However, the spring slammed the BCG forward hard enough that the cases got stuck and were extremely difficult to remove. So, and I hope I didn't miss it above, how can I FL size the body to be usable in my gas gun, but only bump the shoulder 4 or 5 thousandths? VLD Pilot says that the dies just work that way, but that would mean I'd be unable to control the shoulder bump if I size the cases enough to seat in my chamber. Is that true? I've ordered a Redding body die, but as I read more, I'm seeing that that die bumps shoulder as well as sizing the case, so I may not have gained anything - I'll try it when it arrives and report on how it works for me.

 

[Mikecr]

Did the primer pockets loosen some as well?

 

[30BR]

Circling back on this - I did bump my shoulder back .004, but found that the bodies hadn't been sized enough all the way to the base, and the case diameter ended up too large in the last half or 3/4" to allow the bolt to go into battery.

Ask for a small base sizer die. If they don't have one in that caliber, you'll most likely have to send the die and 4 fired cases to someone like Jim Carstensen who will make a die to fit your chamber.

A "Full Custom" Die -- The Total Solution
... If a die that is small enough to begin with can't be found, I can make a full custom die. I have total control over the amount of resize and where the resize is done at. I make a hardened bushing die with a decapping system. I work off fired cases for that chamber. This will cost around $200.00, but it will be a perfect die for the chamber for which it was made. Designed to be used after every firing, the dimensions will give the ideal amount of shoulder bump and body-sizing, no more, no less.

JLC Precision (Jim Carstensen)
[email protected]
13095 450th Ave
Bellevue, IA 52031
Shop phone: (563) 689-6258, cell: (563) 212-2984

 

[Jeffpatton00]

Did the primer pockets loosen some as well?

A few primer pockets did seem much looser than the rest when I decapped the batch,

 

[Mikecr]

Your load is hot and/or your chamber is sloppy, and your default seems to way oversize brass.
Dies will not fix these problems, as oversizing (up/down) does not 'fix' anything..

 

[Jeffpatton00]

Your load is hot and/or your chamber is sloppy, and your default seems to way oversize brass.
Dies will not fix these problems, as oversizing never fixes anything..

I want to be sure I'm understanding your points, MikeCR. I was doing load development so only 3 rounds were over the book's max pressure, and even they didn't show pressure signs - I showed those to some fellow reloaders at the range and they suggested I could go to an even higher max load, based on the lack of pressure signs, so I'm not thinking it's an over-pressure problem unless there's something I'm missing. Regarding the chamber, this is a custom build and the chamber was honed by the smith using a new, custom hone - I was thinking that perhaps the chamber was honed a little tighter than SAAMI, given the seating problems, rather than being sloppy. Is there another way to think about this? Finally, you mention oversizing - since I was focused on bumping the shoulder and didn't size the body all the way to the base, I was thinking I was undersizing the case, not oversizing. Were you saying that by not fully sizing the body, I was leaving the case itself oversized? I really need to figure this problem out so I want to be sure I'm fully understanding people's suggestions.